Pусский
The Marking Rules Of The Dimension Values Of The Mechanical Seals Drawing are the follows：
(1) Basic rules
1. The real dimension of the mechanical seals should be set based on the values of the input on its drawing, which has nothing to do with the dimension written on the graphic and the accuracy of the drawing.
2. The dimension written in the drawing (including technical requirements and other instructions) of the mechanical seal, when mm is used as a unit, does not need to mark the code or name of the measurement unit. If other units are used, the code or name of the corresponding unit unit must be indicated.
3. The dimension marked in the drawing of the mechanical seal should be the final dimension of the mechanical seal of the machine, otherwise it should be explained separately.
4. Each dimension of the mechanical seal is generally labeled once, and it should be marked on the graphic that reflects the clearest structure.
(2) dimension composition
As shown in the figure below, a complete dimension marking should generally include the values of the dimension, the dimension line, the boundary line, and the arrow or oblique line of the dimension line terminal.
1. dimension numbers
The number of linear dimension should be written above the dimension line, and it is also allowed to note at the interrupt of the dimension line.
2. Dimension lines
The dimension line is drawn with a fine line. It cannot be replaced by other graphic lines. Generally, it is not allowed to coincide with other map lines or draw on its extension line. When the linear dimension is marked, the dimension line must be parallel to the marked line segment; when there are several parallel dimensions, the large dimension should be noted outside the small dimension, so as not to intersect the dimension line with the boundary line. When the diameter or radius dimension is marked on the circular or arc, the dimension line should generally pass the center of the circle or extended line. There are two forms of the terminal of the dimension line, as shown in the figure: arrows are suitable for various types of patterns. The B in the figure is the width of the coarse solid line; the oblique line is drawn with a fine line, and the H in the figure is the font height. The terminal of the circular diameter, the radius of the arc, and the dimension line of the angle should be drawn as an arrow. When using a slanted form, the dimensions of the dimension and dimension must be vertically perpendicular to each other.
3. Boundary Line
The boundary line is drawn with a fine line, and it should be led by the outline, axis or symmetrical center line of the graphic. The contour line, axis, or symmetrical center line can also be used as the boundary line. The dimensions of the dimension should generally be perpendicular to the dimension line, and the terminal of the dimension line should be about 2mm.
(3) Example of dimension marking method
Some of the dimensions marking method in the national standards regarding mechanical seals drawings are listed below.
1.Linear dimension digital direction
The first method: The dimension numbers should be written in the direction shown in the figure below (above), and the dimension is marked in the range 30 as much as possible. When it is unavoidable, it can be marked according to the form of the figure below (below).
The second method: When causing misunderstandings, the number of the non -level direction can be horizontally marked in the interrupt of the dimension line, as shown in the two pictures below. In a drawing, the same method should be adopted as much as possible, and the first method should be written.
2. angle
The boundary line should be drawn along the radial line. The dimension line is drawn into an arc, and the center of the center is the apex of the horns. The dimension numbers should be written horizontally. Generally, it is noted in the interrupt of the dimension line. If necessary, it can also be marked according to the form of the right figure.
3. Circular
The diameter dimension of the circle should generally be marked according to these two examples.
4. Arc
The radius dimension of the arc should generally be marked according to these two examples below.
5. Big arc
When the center of the circular cannot be marked within the drawing range of the mechanical seal, you can press (left) icon; you can press (right) to note when the center position is not marked.
6. Small dimension
As shown in the diagram above, when there is no space, the arrow can be painted outside, or the two arrows are replaced by small dots; the dimension numbers can also be written outside or leading to the marking. The small dimension of the circular and arc can be pressed by two examples.
7. Ball surface
The dimension of the sphere, as shown in the left and middle figure below, should be marked "S" in front of the ø or R. When causing misunderstandings, you can omit, as shown in the right -end sphere in the right picture below.
8. String length and arc length
When the length of the string is long and the arc is long, as shown in these two examples below, the boundary line of the inches line should be parallel to the vertical line of string. When marking the arc length, the dimension line is arc, and the symbol "^" should be added above the dimension number "^"
9. Draw only half or more than half of the symmetrical parts
The dimension 84 and 64 on the picture, their dimension lines should be slightly exceeded by the boundary line of the symmetrical center line or the break, and only draw the arrows on the end of the dimension line. Fine thread (symmetrical symbol).
10. board -shaped parts
When the dimension of the plate -shaped parts is marked, the symbol "8" can be added above the dimension number of the thickness value.
11. The dimension of the smooth transition
As shown in the example figure, at the smooth transition part, the outline must be extended with a thin line, and the dimension line of the dimension is led from their intersection.
12. Allow the ruler line to tilt
The boundary line should generally be perpendicular to the dimension line, and it is allowed to tilt if necessary. As shown in the figure above, if the dimension line here is perpendicular to the dimension line, the graph line is very unclear, so it allows tilt.
13. square structure
As shown in the example, when the split section of the mechanical seal is the dimension of the square structure, the symbol "□" can be added before the side length dimension, or the "□ 14" is replaced by 14 × 14 instead of "□ 14". The two thin lines intersecting in the figure are plane symbols (when the graphics cannot fully express the plane, this symbol can be used to represent the plane).
14. Slip and cone degree
The slope and taper can be marked with the methods shown in the following two examples. The direction of the symbol should be consistent with the direction of the slope and the cone. The taper can also be noted on the axis. Generally, the angle value (A is a cone angle) is not required while the cone is marked; if necessary, the angle value can be marked in the bracket as shown in the graph.
The drawing method of the slope and the cone symbol, see the two figures below, they show that the line width of the symbol is H/10, and H is the height.
15. The processing of the figure through the dimension number
The dimension number cannot be passed by any graph. When the dimension number cannot be avoided by the graph, the graph must be disconnected, as shown in the example figure.
